Note on Biotic factor

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source: slideplayer.com fig: Autotrophs and heterotrophs

Living organisms present in an environment which is constantly interacting with one another are called biotic factors. They include all plants, animals, microbes . The biotic factor is divided into two categories on the basis of their nutritional point of view. They are autotrophs and heterotrophs.

Autotrophs

Autotrophs are those organisms that can make their own food. They are also called producers. Autotrophs are the green plant which contains chlorophyll. They synthesize organic foods from inorganic materials. The green plants produce organic compounds, sugars from carbon dioxide and water by the process of photosynthesis.

6CO2 + 6H2O → C6H12O6 + 6O2

Heterotrophs

Primary consumers

Those organisms which cannot prepare their own food and depends onautotrophs for food are called heterotrophs. They come under consumer and decomposer. They are called phagotrophs because they ingest their food themselves. On the basis of nature of food, heterotrophs are divided into the following categories: these are the herbivorous animals which derive their food materials directly from the autotrophs. They are the first order consumers. Eg; rabbit, deer, goat, sheep etc.

Secondary consumers

These include carnivorous and omnivorous animals which derive their food either from primary consumers or from both primary consumers and producers. They are second order consumers. Eg; lion, tiger, hawk, owl, crocodile etc.

Tertiary consumers

These are the top carnivorous animals which derive their food materials from both primary consumers and secondary consumers. They are the third order consumers. Eg: lion, tiger, hawk, owl, crocodile, shark etc.

Decomposers

source: citadel.sjfc.edufig: Decomposer

They feed on dead bodies of organisms and organic wastes of living organisms. They absorb some of the product while releasing most of the inorganic compounds into the environment. They produce the digestive enzyme to break down organic compound and then absorb some of the decomposed product while most of the inorganic compounds are released into the environment. They are also called reducers as they reduce dead remains of organisms.